BTE (behind-the-ear) hearings aids are well-known in the art. A BTE hearing aid has a BTE housing that is shaped to be worn behind the pinna of a user. The BTE housing accommodates components for hearing loss compensation. A sound signal transmission member, i.e. a sound tube or an electrical conductor, transmits a signal representing the hearing loss compensated sound from the BTE housing into the ear canal of the user.
The output transducer may be a receiver positioned in an ear canal of the user of the hearing aid, a so-called Receiver-In-the-Ear. In the following, a hearing aid with a Receiver-In-the-Ear is denoted a RIE hearing aid.
In a RIE hearing aid, the sound signal transmission member comprises electrical conductors for propagation of hearing loss compensated audio sound signals from the hearing aid circuitry in the BTE hearing aid housing through the conductors to the receiver positioned in the ear canal of the user for emission of sound towards the eardrum of the user.
In order to position the receiver securely and comfortably in the ear canal of the user, an in-the-ear housing, earpiece, shell, or earmould may be provided for insertion into the ear canal of the user.
In the following, the terms in-the-ear-housing, earpiece, shell, and earmould are used interchangeably.
Typically, hearing aid manufacturers provide a number of different earpieces with receivers having different output power specifications, e.g. 5 different output power levels.
Typically, earpieces are also provided having sound signal transmission members of different lengths, e.g. 8 different lengths, to suit the individual anatomy of the intended user.
Thus, e.g., 8*5=40 different earpieces may be used together with a specific BTE-housing.
Additionally, in order to fit the user's ear and secure the sound signal transmission member and other components in their intended position in the ear canal and prevent the earpiece from falling out of the ear, e.g., when the user moves the jaw, the earpiece, shell, or earmould may be individually custom manufactured or may be manufactured in a number of standard sizes, which further multiplies the number of earpieces that may be used together with a specific BTE-housing.
The earpiece may further accommodate one or more microphones, e.g. a microphone used for suppressing the occlusion effect and/or one or more microphones for recording directional cues further multiplying the number of earpieces that may be used together with a specific BTE-housing.
This results in a very large variety of earpieces that can be used together with a specific BTE-housing.